Evaluation method of cracking resistance of lightweight aggregate concrete

Abstract

The cracking behavior of lightweight aggregate concrete (LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete (NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζ_t(t) and the evaluation index A_cr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger A_cr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger A_cr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.

Keywords

ceramsite type / cracking resistance / lightweight aggregate concrete / evaluation index / evaluation method

References

[1] TanW-f, WangL-a, HuangC, LiuY-y, GreenJ E, NewportD, GreenT. Utilization of municipal solid waste incineration fly ash in lightweight aggregates [J]. Journal of Central South University, 2012, 19(3): 835-841

[2] CastroJ, KeiserL, GoliasM, WeissJ. Absorption and desorption properties of fine lightweight aggregate for application to internally cured concrete mixtures [J]. Cement and Concrete Composites, 2011, 33(10): 1001-1008

[3] HenkensiefkenR, BriatkaP, BentzD, NantungT, WeisseJ. Plastic shrinkage cracking in internally cured mixtures made with pre-wetted lightweight aggregate [J]. Concrete International, 2010, 32(2): 49-54

[4] SuzukiM, MeddahM S, SatoR. Use of porous ceramic waste aggregates for internal curing of high-performance concrete [J]. Cement and concrete research, 2009, 39(5): 373-381

[5] LopezM, KahnL F, KurtisK E. Characterization of elastic and time-dependent deformations in high performance lightweight concrete by image analysis [J]. Cement and Concrete Research, 2009, 39(7): 610-619

[6] ChandraS, BerntssonL. Lightweight aggregate concrete: Science, technology, and applications [M]. William Andrew, 2003

[7] BenturA, IgarashiS, KovlerK. Prevention of autogenous shrinkage in high-strength concrete by internal curing using wet lightweight aggregates [J]. Cement and Concrete Research, 2001, 31(11): 1587-1591

[8] SahmaranM, LachemiM, HossainK, LiV C. Internal curing of engineered cementitious composites for prevention of early age autogenous shrinkage cracking [J]. Cement and Concrete Research, 2009, 39(10): 893-901

[9] HenkensiefkenR, BentzD, NantungT, WeissJ. Volume change and cracking in internally cured mixtures made with saturated lightweight aggregate under sealed and unsealed conditions [J]. Cement and Concrete Composites, 2009, 31(7): 427-437

[10] BentzD P, WeissW JInternal curing: A 2010 state-of-the-art review [M], 2011, Gaithersburg, Maryland, US Department of Commerce, National Institute of Standards and Technology

[11] ZhangM-h, GjorvO E. Microstructure of the interfacial zone between lightweight aggregate and cement paste [J]. Cement and Concrete Research, 1990, 20(4): 610-618

[12] BentzD P. Influence of internal curing using lightweight aggregates on interfacial transition zone percolation and chloride ingress in mortars [J]. Cement and Concrete Composites, 2009, 31(5): 285-289

[13] GB/T50081-2002.Test standards and methods for mechanical properties of normal concrete [S], 2003, Beijing, China Building Industry Press

[14] JiT, ChenC-y, ZhuangY-z, LinX-jian. Effect of degree of ceramsite prewetting on the cracking behaviour of LWAC [J]. Magazine of Concrete Research, 2012, 64(8): 687-695

[15] ChenYanMix proportion design of high-strength lightweight aggregate concrete and its preformance [D], 2007, Changchun, Jilin University: 63-64

[16] CussonD, RepetteW L. Early-age cracking in reconstructed concrete bridge barrier walls [J]. ACI Materials Journal-American Concrete Institute, 2000, 97(4): 438-446